CVE-2026-46339CWE-306CWE-78

9Router: Unauthenticated Remote Code Execution via unprotected MCP custom plugin routes

Critical · published July 15, 2026

CVSS v3.1
10.0
EPSS
3%
Percentile
88.6
In the wild
Unconfirmed
What it is

9Router is an AI router & token saver. From 0.4.30 until 0.4.37, 9Router's src/proxy.js middleware did not protect /api/cli-tools/* and /api/mcp/*, allowing unauthenticated registration of customPlugins through src/app/api/cli-tools/cowork-settings/route.js and command execution through the MCP bridge. This vulnerability is fixed in 0.4.37.

The record
Technical detail
CVSS v3.1
10.0 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.03352 · 88.6th percentile
Weaknesses
CWE-306 · Missing Authentication for Critical Function; CWE-78 · Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Published
2026-07-15T20:41Z
EPSS history
Timeline
  • 15 JUL 20:41Z
    9Router: Unauthenticated Remote Code Execution via unprotected MCP custom plugin routes
    cvelistv5